August 2008 - Gambit-list - mailman.iro.umontreal.ca

Edge triggered I/O with libevent
by Adam Langley 04 Apr '13

04 Apr '13

Gambit uses the select call on POSIX systems to multiplex IO operations. This is fine for small numbers of file descriptors, but falls apart quickly with large numbers[1]. libevent[2] is a wrapper library around a number of modern IO multiplexing systems (epoll on Linux, kqueue on the BSDs as well as poll and select). Attached is a patch which converts Gambit to using edge triggered I/O with epoll and libevent. This also requires a patch (attached) of libevent since the standard distribution doesn't include edge triggering support and the upstream appears to be on holiday. (epoll is required because I don't have a BSD box on which to develop edge triggering support for kqueue) This patch (for Gambit) preprocesses away to nothing unless --enable-libevent is passed to the configure script. (Note that, since this patches the configure.ac script, you'll need to run autoconf to regenerate). I hope I've not broken anything, but at this stage I've only tested that the console and tcp ports work. This patch (in the future) should also allow people, who write programs which use socket calls directly, to integrate into the main event loop at some point. Testing is more than welcome and, if you find a form of IO which is broken, please email me. [1] http://monkey.org/~provos/libevent/libevent-benchmark2.jpg [2] http://monkey.org/~provos/libevent/ -- Adam Langley agl(a)imperialviolet.org http://www.imperialviolet.org (+44) (0)7906 332512 PGP: 9113 256A CC0F 71A6 4C84 5087 CDA5 52DF 2CB6 3D60

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DrScheme and GambitC
by Nick 14 Sep '08

14 Sep '08

Hello! I believe, every schemer knows about popular IDE DrScheme. It has one nice feature - it allows to choose language level at any time, and this language level vary from very restricted to very rich like MrEd. So I thought I would be great if there was a plugin to DrScheme adding the "Gambit" language level. I searched through web in order to find some pointers how to add custom language level or if people writing their own plugins for DrScheme. But I found not very much :-( If anyone has some info on maybe attempts to add Gambit plugin, or info how to add plugins or anything like this, or finally any advice, relevant or irrelevant :-), please, let me know. With best regards, Nick

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ANN: update to R6RS support for gambit.
by Arthur Smyles 29 Aug '08

29 Aug '08

I've updated my R6RS package for Gambit. 1. Implemented err5rs records as an R5RS as well as R6RS library 2. Changed expander.scm and runtime.scm to use the new record system. 3. Updates for the compile script The latest tarball is available at: http://smyles.com/projects/r6gambit.tar.gz The project homepage is now http://smyles.com/projects/r6gambit The darcs2 repository is available at http://smyles.com/projects/r6gambit/darcs The err5rs records implementation can be independently used for your projects. Just copy the files: err5rs-records-inspection.scm err5rs-records-procedural.scm Arthur

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Namespaces and define-type
by Alex Sandro Queiroz e Silva 26 Aug '08

26 Aug '08

Hallo, Could somebody please explain me these two undocumented features, namespaces and define-type? I see them a lot in the examples, but cannot find them in the manual. :-( Thanks, -alex http://www.ventonegro.org/

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Space Invaders on gambit-c
by David St-Hilaire 21 Aug '08

21 Aug '08

Hi all! I just wanted to let you know that I've just put my space invaders (the classic arcade game) re-make on the dumping grounds. There are also pre-compiled binaries available on my web page (http://www-etud.iro.umontreal.ca/~sthilaid/) The game runs over glut and SDL and should be compatible at least with linux, windows and mac systems (execpt that the glut user interface does not seem to work in windows...). Compilation insights is provided in the README file. Just send me a mail for help, question, comments, or most likely, bug reports! ;) Enjoy! ^_^Y David

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Speed on XML-parsing
by Hans Petter Egesund 18 Aug '08

18 Aug '08

> Yes, bash. > > I copied the line from Bradleys mail, but I was wondering about the > same thing, as well. I am not really sure what the expansion-option > means in Gambit. > > Petter > > Den 17. aug. 2008 kl. 16.41 skrev Christian Jaeger: > >> Hans Petter Egesund wrote: >>> I did a: time gsc -keep-c -expansion ssax-sxml > ! expansion.scm >>> >> >> Wondering: is this in bash? If so, why are you putting the ! >> there, do you want to capture the expansion in the "!" file? What >> is expansion.scm, a previous expansion? >> >

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Re: [gambit-list] Speed on XML-parsing
by Hans Petter Egesund 17 Aug '08

17 Aug '08

Hi, more on slow xml... I can't get ssax to parse from a string, it seems the library is using input-port-byte-position which needs a device input port. So the attempt so slurp the file into memory, and then do the parsing ends here?! I will tell if I come up with something interesting. Petter

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Getting SSAX-SXML going on Gambit
by Mikael More 16 Aug '08

16 Aug '08

Is anyone having problems compiling SSAX-SXML on Gambit? We used Dominique Boucher's SSAX-SXML. It can be found on the Gambit page's dumping grounds. Essentially there has been two issues with this distribution, both of which are easily fixed: - Add namespace to the distribution. This is done by adding -prelude '(##namespace ("ssax-sxml#")) (##include "~~/lib/gambit#.scm") (##include "~~/lib/ssax-sxml/ssax-sxml#.scm")' to the gsc compile rows in the Makefile. Make ssax-sxml# contain (##namespace ("ssax-sxml#" [list of the ssax-sxml functions you want to use] )) . - Patch the srl:appy-string-append of sxml-tools/serializer.scm , in order never to pass string-append more than 8192 parameters. We did this through rewriting it to use a string port instead. Having this not fixed does cause a problem, I think it is when serializing SXML to XML without passing a port parameter. Also I have a lose memory that that SSAX-SXML distribution is compiled with (declare (not safe)) by default, which may not be preferable. M 2008/8/16 Bradley Lucier <lucier(a)math.purdue.edu> > > On Aug 15, 2008, at 10:00 PM, Frederick LeMaster wrote: > > > > > Adjusting gambit to accept .c files not in the current directory will > > allow SSAX to build. > > There's a patch for that in bug #41. > > That's not enough for any of the SSAX sources I found (CVS, the > gambit one from 2006) to build using the Makefiles. > > Brad > > _______________________________________________ > Gambit-list mailing list > Gambit-list(a)iro.umontreal.ca > https://webmail.iro.umontreal.ca/mailman/listinfo/gambit-list >

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Speed on XML-parsing
by Hans Petter Egesund 16 Aug '08

16 Aug '08

Hi, I have some large xml-files which I have to parse, and I have used latest Gambit + ssax on my 64-bit (now :-) computer, Linux. My program parses my file in 150 seconds. After adding (declare (not safe... ) and so on, and compiling with -02 I get it down to 140 seconds, tweaking ssax itself the same way gives me 115 seconds. The parser is so far doing nothing - it just runs through the data. Doing the same thing in Java takes about 3 secs, using expat from C makes it 2 secs. But my math works blazingly fast in Gambit. Is there any thing I can do to make the xml-parsing faster? I have found some papers that claim ssax to be as quick as expat (http://okmij.org/ftp/Scheme/SSAX-benchmark-1.html) - as I have some thousand of these files to parse, a speedup would really make a difference. Clues on this one? Cheers, Petter

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What is the best way to handle enums?
by Frederick LeMaster 16 Aug '08

16 Aug '08

In the FFI you can take an enum such as the following from the SDL library: typedef enum { SDL_GL_RED_SIZE, SDL_GL_GREEN_SIZE, SDL_GL_BLUE_SIZE, SDL_GL_ALPHA_SIZE, SDL_GL_BUFFER_SIZE, SDL_GL_DOUBLEBUFFER, SDL_GL_DEPTH_SIZE, SDL_GL_STENCIL_SIZE, SDL_GL_ACCUM_RED_SIZE, SDL_GL_ACCUM_GREEN_SIZE, SDL_GL_ACCUM_BLUE_SIZE, SDL_GL_ACCUM_ALPHA_SIZE, SDL_GL_STEREO, SDL_GL_MULTISAMPLEBUFFERS, SDL_GL_MULTISAMPLESAMPLES } SDL_GLattr; What is the best way to define this as a foreign type? If you do the following: (c-define-type SDL_GLattr "SDL_GLattr") Then to get at the values you have to assign a pointer to the enum value (c-lambda () SDL_GLattr "___result_voidstar = &SDL_GL_SWAP_CONTROL;") Seems like passing the actual value would be preferable. Am I missing something obvious?

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